Month 1: Buy $3000 each of product 1&2
Month 2: Buy $3000 each of product 3&4
Month 3: Buy $3000 each of product 5&6
Every 3 months you will achieve target asset allocation.
I look at % variance from my target allocation as an indicator to make changes. Initially, if your portfolio is small, then the monthly $6000 will cause larger deviations from target, but even after a year, the effect will be minimal.
This plan is a simple one for you to get started. In the future, after your portfolio is larger, just buy into the two funds that are deviating the furthest away from your target.
Keep it simple, keep it systematic, and you'll reap the most benefits from diversification.