This verse has a number of confusing elements in it. These are smoothed over in translation. The main problem is the mixture of a future tense verb with a verb in the past perfect tense.

"Here after" is the Greek phrase of three words meaning "from the now" or "from the present". The word  "from" means "from" in both location and when referring to a source. The "the" is the Greek definite article, which usually precedes a noun and, without a noun, takes the meaning of "the one." The Greek article is much closer to our demonstrative pronouns ("this", "that", "these", "those"). See this article for more.  The Greek word s "now" means "now", "at the present moment","presently," and "as it is."

There is an untranslated word here in the Greek. It means "but", "however", and "on the other hand". Since it always falls in the second position, translating it as "however" often captures its feeling better. 

The verb "shall" here is the common form of "to be" in Greek. It means to have a certain characteristic or remain in a certain condition. It also equates terms or assigns characteristics. The form is the future tense.

The phrase "the son of man" is the common way Christ refers to himself. It is discussed in detail in this article. Its sense is "the child of the man." The word translated as "son" more generally means "child" or "descendant". The Greek word for "of man" in the singular means "person" and "humanity" and "people" and "peoples" in the plural.

The next word is confusing because of its tense. Greek word translated as "sit"" means to "sit," especially of courts, councils, assemblies, etc. As a noun, which is how it is used here, it means "the judge," or "the court."  Jesus seems to use this word exclusively to refer to sitting in judgment of others. What is confusing is the form which is in the form of an adjective "sitting" but in the past perfect tense describing something completed in the past, "having seated himself". The "himself" comes for the voice which indicates someone acting on himself.

The Greek preposition translated as "on" means "out of" or "from." In Greek, they use the genitive case instead of a preposition for the types of phrases with usually use with "of." This idea of being seated on the right is not usually indicated by this preposition.

"The right hand" is dexios, (maybe) which means,as a noun, it means the "right hand," "assurance", "pledge", and "treaty."  However, the form, which is plural, is confusing unless you take it as a reference to the Trinity. This word could also be a particle of  two different verbs. One means "approve" in the future tense so "going to be approved" and the other means "bring to light" in the future so "is going to bring to light". This looks like wordplay to me.

 "Of the power" is a word that describes abilities and capacities, what actions a person can do or has done so "power", "might", "influence", "authority," and "force." It does not carry the sense of authority over others, either people or laws. The verb form of this word is translated as "can" in the NT. The "of" comes from the form of the word. Itis re

The word translated as "of God" means "God" and "deity." It is introduced with an article, so "the God." Jesus often uses it this way perhaps to indicate the one God as opposed to the pagan gods.