on number 2:

there are many ways to join objects

Are they even object? Heres an example with 2 cubes -

right click to show vertex - hold down v and middle mouse click it and drag it to the other vertex then it "snaps"

then you can go to polygons (highlight the vertex`s) and merge muliple vertex - or merge the edges the same way - using the merge edges tool.

loads os way to do these things mate, maybe might be good to give the old F1 button a try to look for the basic -helps so much