Verb conjugation of "grade" in English

Dear Maximilian, I look forward to your visit in Switzerland. After a somewhat difficult start, it seems that we have increased the website traffic and we are starting to receive more visitors.
Thank you for your email! A little question about yourself. How old are you? I think the Americans are using the word color and not colour, but I understand if you are not sure about it.
Now I am learning by other means, such as reading and writing. I can not begin with conjugation training because I lack the basic knowledge. How are you learning at this site and which is your best lesson?