Welcome JohnyCat
Regarding the MOD
SH5 ... TWoS simple installation
SH3 ... GWX simple to install
LSH. Easy to install (but before starting I suggest you read Theberbester advices.... Very useful)
WAC.... not for old PCs simple to install but necessary to install JSGME first
And Important... Install steam outside Program(x86) folder!!! NO forget this
My 2 cents...