How do you appraise an apartment building?

[Ryan Lee]

So there is an apartment building I am trying to appraised but I need some assistance. Its 2 buildings attach to each other but has 2 separate address. 

The bottom floor is a restaurant and its spans the entire area of both buildings A & B. 

Building A has

1 apt  on floor 1

1 apt on floor 2

Building B has

1 apt floor 1

1  apartment that spans across building A&B floor 2

1 apartment that spans across building A&B floor 3

so there is a total of 6 units, How do i figure out whats it really worth?