This is a deeply interesting question as Liberia is certainly a very unique country. Unfortunately, instead of integration and cohabitation, the indigenous population was subjected to a brutal and exclusionary oligarchy that some have gone as far to describe as "black colonialism".
The descendants of the 300 black slave families that were emigrated to Liberia called themselves "Americo-Liberians" and immediately took on the role of the superior class. It is worth pointing out that these families had been subjected to enslavement accompanied by the complete removal of their heritage, home, and character while toiling in the Southern plantations. They had only experienced the world through the lens permitted to them by their owners and freedom was idealised as Southern habits and society. The new arrivals immediately set about mirroring that behaviour by building their new home in the style of the Antebellum South. The capital, Monrovia, was full of pillared porchways and neo-classical buildings occupied by gentlemen in top hats and morning dress. However, under this somewhat quaint time capsule was a dark streak of ethnic tension.
Christian identity was deeply important to slaves and ex-slaves and these strong beliefs traveled with them to Liberia. The indigenous population was immediately viewed as barbaric heathens and therefore not part of the society they wished to build. Relations had already been irreparably damaged by the new arrivals attacking tribes to take more land on numerous occasions in the 1820s and 30s. On top of this, an exclusionary system was created forbidding the indigenous population to vote, own land, or participate in civil society. This was not grounded entirely in racial superiority, but more a cultural one. Unfortunately, the belief in which culture was superior derived from the acute Southern racism the immigrants had experienced in the South.
Some efforts were made to assimilate, as opposed to integrating, with the population but it was heavy handed enough to cause further tension and half hearted enough to have not much of an impact. The one party government (The True Whig Party) the Americo-Liberians created encouraged urban building projects to try and create centres of their own cultural power and authority across the country and exclude or remove local indigenous settlements. This was a very disruptive way of trying to encourage the natives, colloquially called "country boys", to move into their orbit and live and act like them. Some children were forcibly adopted by Americo-Liberian families which did little but antagonise the relations between the two groups.
Although it is a struggle to find primary sources on exactly what the native population thought of their new overlords, the narrative speaks for itself. They were almost immediately met by violence followed by a culture war against their traditions and character. Whig Party rule continued for well over 100 years until the last President of Americo-Liberian heritage, William Tolbert. The level of corruption under his rule was staggering with family members running, and profiteering, multiple government departments on top of a deeply ostentatious lifestyle in stark contrast to the living conditions of the native population.
In 1980 the situation reached boiling point and following an increase in rice prices, strikes and demonstrations broke out. Led by an indigenous Liberian, Samuel Doe, the protestors stormed the Presidential Palace to execute Tolbert followed by gouging out his right eye and disemboweling him. The feelings of the majority population are best exemplified by the shouts of one during the mass execution of government officials following Tolbert's demise, "Freedom! We got our freedom at last!"
Further reading:
Meredith M, The State of Africa (London 2013)
Holsoe S, ' A Study of Relations Between Settlers and Indigenous Peoples in Western Liberia, 1821-1847', African Historical Studies Vol 4, No2 (1971)
I asked a similar question a while ago and got this great answer about Liberian history by u/q203, and it seems to touch on a few aspects that the other great comment in this thread doesn't.