A lot of specifics depend on your workflows, but the data structure options are pretty straightforward.

If you are just concerned about getting guests to tables but NOT assigning specific seats what you want is a table of tables that probably needs a table number for the hotel, a table name to print on the sign, a max number of seats, a count of seated guests and a link to the guests table which will have your guests. To seat guests just attach to tables.

If specific seats matter you will need a third table between the guests and the tables for seat assignments attached to tables. Another way would be to just have a big table of seat numbers and a drop down for tables but that probably does not scale.

Source: have been doing event databases of various flavors since last century.