What's the difference between a past and past participle/present and present participle?

Past is something that refers to time before now. (If you were thinking about past tense, it is verb tense referring to the past.) Past participle is the form of the verb that is used in perfect tenses and in passive voice. Present is something that refers to the present time (existing or happening now). (If you were thinking about present tense, it is verb tense referring to the present). Present participle is the form of the verb that is used to make continuous tenses, such as Present Continuous Tense, Past Continuous Tense, Future Continuous Tense, etc. It ends in suffix - ing.