multithread a code on c#

i developed a simple program on c# that loops through links added to datagrid and it navigates to each url from datagrid with selenium chrome browser what i need is to use textbox to control the number of threads. , for example , if i run the code and increase the textbox number, for example from 1-n the program will open the number of threads according to the number i selected on the textbox so in general, i want it to keep to the number of threads selected on the text box , please bid only if you have done something like this before and please note you are only going to multi-thread already written program, you are not going to write any form of new project , just only multi-thread take a look at the one we did with another language here [login to view URL]