A couple of noob questions

[Blue Proteus]

Haven't played in years, and am coming back to check out the crafting, which is pretty lame these days in most mmorpgs.

But I'm having a heck of a time getting started.

Questions:
When I accepted the role of the cleric (or the warrior, or the mage) the trainers gave me "Letters of Credit". What do I do with these? I tried interacting with the proper salesfolk, but they told me they weren't interested in the letters. So how do I trade for my free starting gear?

I trained for blacksmithing, and got my starter tools. I mined copper and tin ore till my inventory was full, but my inventory isn't full, it's got a lot of slots left...so what is this limit based on? Weight? Number of items?

What do I do with the ore I've mined? I received formulas, am I supposed to memorize them somehow? I guess I need a newbie crafting guide, as I don't understand the steps involved.

Am I correct in assuming that I can't actually be a warrior, and a mage, and a cleric? Although the trainers gave me stuff and welcomed me, the next day when I logged in it said they had been disabled "due to a constraints or school check". Huh?

Are there limits to which crafting types I can learn?

Thanks!

[Sigi]

Dit you do the quests on the starter isle? Spirit isle is it called if I recall right. I believe it is all well explained there.
But

Letters of credit
Have those in your inventory and greet the salesfolkp, so not trade but greet.

Your Inventory is full if either you reached the maximum bulk (with pe a lot of ore) or if you have the maximum of number of different items.

The ore you can smelt into bars using the smelting tongs and a smelter. You scribe the formula - right click, choose scribe and it will appear in your knowledge book.

You can be in one adventure and one craft school at the time but you can change whenever you want.

You can learn all the crafting types, it is only limited by the time you wish to spent

Have fun!