For es/fr/nj users - in PartyCapiton v1.87f versions you still can use full-featured betscript. You can read about Betscript settings in 888Caption description - it has mostly the same settings for Basic and Advanced betscript.
In partypoker.com there are allowed to use only two predifined bets - one for preflop and one for postflop.
Default preflop bet
Here you can configure a default preflop bet. It will be used for all preflop situations - openraises, isolates, 3bets, etc. You can choose one of two possible ways to configure bet size - Big blinds or % of pot. For example, you can configure 3bb here, or 100% of pot (it will be pot size raise for all preflop situations).
Turn on Active if you want to use this option. If this option disabled, then you will have minraise as default bet size in all preflop situations.
Default postflop bet
Here you can configure a default postflop bet - by the same way as for preflop.