Boosting isn't a problem. Just read your skills and practice on a training dummy and you should be able to figure out a basic rotation. If you're in the novice network, you can also ask an experienced RDM for additional help.

The basic idea of RDM is to increase your Black and White magic evenly to spend on powerful melee attacks. RDM spells also grant the dualcast buff which lets you a follow up spell instantly. Use this to get around RDM's longer casting spells. As a starting point practice building your white/black mana to 80/80, which is what you need to begin your enchanted melee combo:

Build mana with spells > Reach at least 80 in both black and white mana > Corps-a-corps gap closer to enter melee range > Enchanted Riposte > Enchanted Zwerchhau > Enchanted Redoublement > Displacement will push you out of melee range > start over

AoE is similar, but replace the Enchanted combo with Enchanted Moulinet.

The rotation I outlined above doesn't include everything (most importantly Manafication and Verflare/Verholy) but it's the core of RDM's playstyle and should provide some context to keep in mind when figuring out how to use skills.