I have played lots of D&D but to date have never multiclassed in 5e. I have a question:

- when I take a level in another class (in this instance a lvl5 Fighter taking a level in Rogue) do I gain the SKILLS and PROFICIENCIES that a normal brand new lvl1 character would obtain?

As a fighter, you already have all the weapon and armor proficiencies of the rogue, but you would gain proficiency in two skills and in thieves' tools.  Plus the Expertise and Sneak Attack.

In reply to phoenix9lives (msg # 2):

Thanks!

Actually, according the the PHB, it's ONE skill and thief tools (also light armor, but that's moot hen starting as a fighter). That's for Skills and proficiencies. And this assumes a Dex of 13 to qualify to multiclass.

Normal class abilities are also gained (in this case the above mentioned Expertise and Sneak Attack, and, also, Thieves' Cant) at 1st level Rogue, but they aren't really skills/proficiencies.

The PHB covers multiclassing starting on page 163, and page 164 goes into what you get when first assuming a new class. If the character is an Eldritch Knight and/or becomes an Arcane Trickster there is some information about spells you'll want to look over.

Ultimately, the DM has the final say. Almost all DM's that I know, use their best judgement in deciding what Player's Handbook rules they follow. It's best to give the DM any questions/concerns in creation of a character in their campaigns.

Thanks all…