Step 1: Review investment terms with lawyer.

Step 2: Sign term sheet with investor but do NOT take the investment.

Step 3: Incorporate, assign equity to founders (at near zero valuation), sign employment & founder agreements, assign any past IP (if applicable).

Step 4: Execute investment agreement and collect money.

Doing it any other way means that you will be struggling with tax liability issues from day 1. Once the money is invested your shares have a fair market value and any founder equity you assign will create a tax liability for the founder (but without liquidity).

A good lawyer should lead you through all these steps for maybe $2k-$5k depending on the complexity of the terms and your location.