Happy New Year!

I have a small dining room , about 3mx2.5m, currently carpeted and am
thinking of replacing this with wooden laminate flooring. The actual
floor underneath is concrete.
Happily, I have no skirtings fitted as I've removed these, having just
had the walls replastered.
So, carpet, underlay and grippers are coming up at the weekend.

I don't know much about laminate but I imagine I want some 'underlay/
foam' stuff down on top of the concrete, take the laminate to the
walls with a small (10mm ?) gap all around, then put the skirting
boards on last, allowing the floor to 'float' - is that about right?

Now, laminate flooring is available from Wickes, B&Q, IKEA, etc. Is it
all pretty much the same re. choice of colours and quality? Am I
likely to have trouble fitting it myself?
Are the 'locking' panels equally effective and easy to snap together
without special tools?
Any recommendations for other suppliers?
What should I put underneath it?
Anything else I should bear in mind?

Many thanks,
Jeff