OK I now understand that I can run these commands within phpMyAdmin by selecting the database, going to SQL, opening each of the dated files that pertains, copying the code within, pasting it into the box and pressing 'Go'.
My installer still says this:
DB Schema: NOT OK(Database schema differs)
Missing table 'cache_index'
Missing table 'cache_thread'
Missing table 'cache_messages'
Missing columns in table 'contacts': words
Missing table 'dictionary'
Missing table 'searches'
Missing table 'system'
- but the installation seems to be functioning and I can verify that those tables do in fact exist.