Answer:
It is a complex sentence.
Explanation:
There are four basic types of sentences: simple, compound, complex, and compound-complex.
A complex sentence has one independent clause joined to a dependent clause by a subordinating conjunction.
An independent clause has a subject and a predicate, and can stand alone as a sentence, as it makes complete sense. A dependent clause cannot stand alone.
In this case, "Kenneth sat down on the rickety old chair" is an example of an independent clause. "as it abruptly collapsed beneath him" is a dependent clause.
If you want to make a past emphatic tense, you need to use the verb DID + the present form of that particular verb. Assuming that the verb you need is TELL, the correct answer here would be did tell.
We did tell you how to find our house.
