hello , i hope this answers your questions
1. when you add م to the verb the word become noun example : انا احتاج i need , and قابلت رجل محتاج i met a man in need (poor)
2. the same with عرف and معرفه , معرفه means knowledge example ,مع القراءه تزداد المعرفه with reading knowledge increase .
3. ذهاب like going and its noun also example : like this plane ticket is two way , هذه التذكره ذهاب و عوده
4. i know : انا اعرف , i am knowing : انا اعرف also , because we have only present tense in Arabic so it will be the same meaning with or without (ing)