Payment terma related

Hi,

I m seting the payments terms , the lsist provided to me has some terms stating as lette of credit or cash in adavnce wiht the net days and disc days specified ( for e.e 1% 10 days, 30 days net , letter of credit or jsut 30 days net, no disc - letter of credit or cash in advance ).

please let me know what loc and how it works or put into sap.

thanks