The first thing is to look at the layout of the rooms and see if you can picture yourself living there. Where the toys go, where you'll sit with your coffee, etc.
Notice the feel of the building- it's hallways, grounds.
The neighborhood, the block.
If you like it, you put in a bid. If the bid is accepted, you bring in an inspector (I actually am not sure this step happens with a condo, bit it certainly is necessary in a house) to look check out the structure. The roof, plumbing, electric, A/C... If the inspection finds a major flaw, you try to get the price lowered based on the cost of repairs.
Then you sell your house to get the money, and then close on the new property.
And move.