You will probably need to disable the Java compatibility checks, and if you have sufficient RAM, increase the allocated memory.

ONCE YOU ARE LOGGED IN...

You may wish to use the map with the M key.

Chunks which have been 'claimed' will be highlighted.

Unless the owner lets you, you can't mine, steal, or interact with anything in a claimed chunk.

Please don't claim massive areas, or the 'starting' dirt house!

There are a lot of new items and recipes in this modpack....

For your convenience, Just Enough Items (JEI) is installed (open your inventory).

Hovering the mouse over any item and pressing R will show you the r>ecipes to make it.

Hovering the mouse over any item and pressing U will show you the usages for that item.

Use the search bar at the bottom right to discover new items and recipes.

For further ideas, guidance and inspiration on what to do with all the mods...

Try looking at the 'quests' menu, accessible from the inventory screen's top left corner.

This Youtube playlist is also excellent.