Whats the deal with wills?

[Jack91]

Hi all,
Had a major whoopsie at work last week, got me thinking about how im nearly 30 and got house, cars and stuff and no will.
Really messy family, want it all to go to my partner of 6+years but we arent married. I can see it being contested by my family but im adamant they get 0.

Do i have to pay for a solicitor or will an online one that i print out be ok?

Also, should i name a power of attorney? I cant imagine my partner would make smart decisions in selling my stuff if i died.

Experiences?

Nb:never married, no kids