how to check oil level on 2006 optra lt wagon 20,000 ks

This may not have a dip stick, so there would be a fill plug on the trany somewhere, the oil level should be even with the internal threads for the plug, to no more than a 1/2 inch below the threads. May just be easier to go somewhere to have it checked. Also it would be a good idea to have the trany filter and fluid changed out.