Bathroom renovation DIY possible?

hi i would like to renovate our bathroom which is very old (i am guessing it was last done in the 70s, bathroom doesn’t have toilet). i live in melbourne australia and i am just wondering if it is feasible for a beginner to buy the shower base screen bath and sink and install it myself? i am reading a lot on this topic and for you expert out there can someone also explain what a wet-sealing is? thanks in advance guys