Hi Billy.
iam old school when it comes to terracotta , i would seal with boiled linseed oil before tiles go down , 1st coat i use boiled linseed oil and white spirits 75% and 25% if dries to quickly re-apply , normal i would leave over night so it can dry properly , make sure you seal floor area with a good primer , use rapid set addy which helps in not staining terracotta , work as clean as possible making sure you clean off any access you drop on surface with clean water
Once you have laid floor seal again with boiled linseed oil 50% and 50% white spirits leave for 10-20 minutes and wipe off with white spirits to remove access linseed oil , only grout small areas when doing terracotta as it will dry quickly even though you have seal tiles , remove access with clean water . once you have grouted leave to dry for 1-2 hours then wipe tiles off with clean dry cloth , leave to dry over night , then i use 75%white spirits and 25% white spirits for final clean , allow to dry ,
Then i use a good beeze wax for top coat , i would hire a small polisher for polishing wax in , follow instructions on tin as they all differ in drying time , once it starts to turn use polishing machine to bluff to high finish , and beleive you me you will be happy with finish
Juts to say there are other ways of doing terracotta by using modern sealers , but to me the will never match the finish of boiled linseed oil and a wax finish , but i will leave that to others to give you that information