What is the procedure to fix a double outlet right ventricle?

Depends. The choice of corrective surgery(s) for double outlet right ventricle depends upon the associated structural abnormality (ies) inside of heart, e.g., pulmonic stenosis.
It depends. Best case scenario the vsd is closed with the lv outflow baffled through the vsd, creating normal blood flow. If either the pulmonary or aortic valve is malformed, the lv outflow is still baffled to a great vessel, and a conduit may need to be placed from the rv to the pulmonary branches. Occasionally the lv may be too small, and a single ventricle repair required.