so this is my firs eu4 game i am castille in 1493 i have aragon and napels in a pu thlemcen is my vassal i had 1 war with portugal, took some provinces. my current goal is to try and make them my vassal, hopefully this can happen after my 2nd war with them(they are at war with morocco, so this will weaken them) my first war with portugal not the best war strategies a few rebbel things drained my mainpower pretty bad

but now i want to attack/conquer france because they are not doing really great(allso not really bad) because they have been involved in many wars(often with burgundy).

so how do i do it? i can only get claims on 2 of their provinces (bearn and poitou) do i continue trying to vassalize portugal first? do i strike now( they just had a pretty big war, but my manpower allso is kinda low) or do i wait until i recover from this? and what is the best moment to declare war. do i try to ally burgundy or austria and go to war with them against france? or do i wait until france is at war again(probably with austria or burgundy) and is weaker? this way they will be occupied in 2 wars

every bit of info/advice is welcome