#OrderTypes101

Here is the detailed meaning:

Order Types = Order Types (commonly used in contexts of investments, trade, or purchase/sale orders).

101 = A basic introduction or initial guide on a topic (comes from the numbering of introductory courses at universities in the USA).

So, #OrderTypes101 would be a faithful translation, used to indicate introductory content about different types of orders. If referring to orders in the financial market, this is perfect. If the context is different (such as product orders, for example), I can adjust the translation as needed.