The War of the First Coalition is Revolutionary France. The Napoleonic Wars are coalitions 3-7.

Assuming we're sticking to the War of the First Coalition, the first major effort was the levée des 300,000 (predating the more famous levée en masse), enacted in early 1793. Each department was given a quota and left to its own devices to come up with a way of filing that quota, "by whatever means they found most suitable, by a majority vote." It ultimately fell to the mayor and the municipal officers to come up with a system of conscription and enact it. Different populations were affected by, and reacted to, the levée des 300,000 in very different ways. The divisions below generally follow along the lines of the Vendée, but wouldn't hold for all of France. Just down the coast in Bordeaux, we have an example of an urban center in which recruitment is much less successful than its surrounding rural areas. Bordeaux's example is exceptional and would shortly draw the intense attention of the Jacobins.

There's also going to between variation between departments and there's going to be variation within a single department. If you're a republican living in an urban area, you may already be a member of the National Guard or an officeholder, meaning you're exempt. If you're a peasant in the Vendée, you will probably find out through word of mouth--the call to arms was published in early March 1793, but there's a good chance you're illiterate. The actual method of conscription again varied by region, but was most often the drawing of lots. Local elites had a few different ways of ensuring their lot was never in the ballot box (triage au sort) to begin with, generally claiming exemption, outright bribes, or paying for a substitute. This uneven application was not lost on the less fortunate. Efforts at public nominations (scrutin révolutionnaire) carried its own risks, such as in Sarthe where popular resentment caused the population to demand that the educated, land-owning elites, who had benefited the most from the Revolution, be the first to volunteer to defend it.

For the peasant, this probably doesn't seem unusual per se. You aren't that far removed from the memory of the pre-Revolution milice, a form of forced conscription that was used to supplement the professional army. You are, almost undoubtedly, going to be very upset. In fact, you were probably upset before all of this. Months prior, there was an anti-revolutionary attack on Bressuire and Châtillon. You don't think of yourself of French in a broad republican sense, Paris has already been messing with your local priest, and the National Assembly got rid of the milice to your great relief. Now it seems like it's coming back. On a much smaller scale, there have been growing tensions and disruptions locally between the rural and urban populations, upending traditional social organization. Desertion rates are high (although highly variable by region), so that may seem like a good option. And if we stick to the peasant from the Vendée option, you may decide on something much bloodier than slipping into the frontier.

Switching sides, let's return to the urban bourgeoisie. You have ever-increasing economic ties to other part of France. The Revolution has done a lot to remove all the infuriating internal tariffs of the ancien regime so you might be very much seeing the benefits of this republic-building project. If you're a good student of the Enlightenment then you may feel a genuine sense of patriotism. And if you're not, you have have the means to find a substitute. Cities had already been driving militia enlistments, first Angers in 1789 but then many of the other cities in the region by 1790. Patriotic life, be it enlisting in a militia or celebrating the first anniversary of the fall of the Bastille, is a largely an urban activity.

Ultimately, your response to the levée des 300,000 will depend on a number of already-drawn lines--class, region, confession, and so forth. Your chances of getting out of service were pretty good; the levée des 300,000 managed to raise about half of its goal, but that "luck" was applied very unevenly among different populations. The failures of the levée des 300,000 speak to a wider problem of a lack of centralized administration during the period. Local officials weren't entirely clear where their authority ended and, in many cases, could do little more than ask nicely. The center had not yet dominated the periphery.