

To freeze your credit means that you (or anyone inpersonating you) can do anything that requires your credit. Cant make large purchase, take out loans, etc. Its a good way to protect yourself from identity theft.
To unfreeze it, you need to go through a process with the credit union before you can use it again. Its generally a good practice to freeze your credit always if you can plan ahead for large financial purchase
In addition to the target date funds, there are some very basic funds through every broker. Some big ones like SPX and QQQ track directly with the s&p and NASDAQ. Every etf will have a theme (tech, biotech, industrial, energy, etc.) And should have a short description on them. Find something that fits your fancy if you have an industry you really believe in