Slip and Fall Injury Claim Advice Needed

I slipped on a wet floor in a local supermarket last month and injured my knee and wrist. I have medical reports confirming the injuries. The store had been notified of the spillage but hadn't put up warning signs. I've been off work for three weeks and have medical bills mounting. I need initial advice on whether I have a viable claim and what the next steps would be. I'm hoping to resolve this without court if possible.