- I'm not a huge expert on 1, but the general answer here is "with difficulty". Unless you made it to Normandy/Brittany for the 2nd BEF's evacuation in late June 1940, you had to somehow smuggle your way out through Spain/Portugal (this is how General Leclerc, later commander of the 2nd Free French Armored Division got out), or through various French colonies/neutral territory. This was a major part of the reason why Free French Forces were extremely small early on (Also the fact that De Gaulle was widely considered to be a fringe figure for a significant amount of time- for example, some of the French troops evacuated at Dunkrik/from Narvik were still in the UK after the French surrender, and while many chose to stick with De Gaulle, the vast majority chose to be repatriated to Vich France).
The vast majority of Free French units in 1940 would be formed from men outside metropolitan France at the time of surrender, various colonial garrisons that joined De Gaulle (Especially French Central Africa - some of the men there would eventually become the core of the Regiment de Marche du Tchad)), and, eventually, in 1942, ex-Vichy units presuaded to join after Operation Torch (this is really where most of the Free French Army that landed in France in August 1944 ended up being from).
- Free French units were formed into their own seperate units, with French leaders/commanders, though under overall British command (Eventually, after the signficiant expansion of French forces after 1942, larger French Corps and eventually an entire French Army was formed, and they generally shifted to American operational command around this time). They would generally be given British equipment initially (because they couldn't get any more French equipment for obvious reasons!), and later, American equipment (The transition to American equipment tended to happen around 1943).Some of these units would go on to long and distinguished careers - e.g. the 13th Demi-Brigade of the Foreign Legion fought in Syria-Lebanon, in the Western Desert at Bir Hakiem and Alamein, then in Italy, before landing in the South of France and finishing the war in Germany. However, you also had French troops serving more tightly within British formations such as the French elements of No. 10 Commando (which was a mixed nationality unit containing men from all over occupied Europe).
The Free French Navy was initially extremely limited - a few destroyers (especially because the British attack at Mers-el-Kebir did not go down well), but were bolstered by ex-Vichy ships from Dakar after the German occupation of Southern France in 1942 in the wake of the Allied invasion of French North Africa. Some of these ships (Montcalm, Georges Leygues etc.) would play a role in the invasion of Normandy.
There were also small Free French air contingents at the start as well, though later in the war, a lot of French units would end up under RAF operational control and given RAF squadron numbers (especially 340 Squadron). A small contingent of French pilots also volunteered to go fight in the Soviet Union with Soviet planes - forming the Normandy-Niemen Regiment.
One interesting quirk of all this is if you look at the modern French Army order of battle and find an extremely oddly named unit - chances are it was one of the hodgepodge of units that rallied to Free France back in 1940-44!EDIT: Formatting.