Help with Type. End Type element selection

Hello Everybody,

Newbie Excel vba user (and poster).
I actually have three simple questions, please
The first is as per the title. I have used this construct because I have mixed data types (dates, strings, singles etc) and I believe they do not fit an array. So how do you select an element from this construct? Or does it have an auto index or similar?
Second question: How do you call an excel formula with vba? Eg Linest(y's, x's) is it:
some variable = xlLinest(range, range)?

Third question: Ranges?
If I have Dates and Sales as two elements of my Type construct (above q1) and I want to linear regress Sales against dates (above q2) how do I set up the ranges (y's and x's)

I thank all assisters in advance. My attempts at getting this info from help files and google queries was not much help. So in desperation I turn to the electronic manual and experience
Regards
Murray

Thank you Rory.
I think I had the first bit, so Q1 rephrased is (say) having populated array "y." with data records, how do I the select an (record) element from it eg the fifth record? Or is it as simple as "y."(5)? See below
Q2: Solved - thank you
Q3: say my array has 12 records (eg months of data - see below for an example) and I want to smooth the data, do I dump the array element out (ie unpack just the sales info eg y.mySingle) or do I access the data with Range (y.mySingle(Range?(what):Range?(what)

R#1: y.myDate ="Jan 10", y.mySingle = 123, y.myString = "Southern", ...
R#2: y.myDate ="Jan 11", y.mySingle = 456, y.myString = "Southern", ...
R#3: y.myDate ="Jan 12", y.mySingle = 789, y.myString = "Southern", ...
R#4: y.myDate ="Jan 13", y.mySingle = 212, y.myString = "Southern", ...

I hope this is not too dumb! I do not have Excel data loaded yet because I wanted to build my solution first so I know how to import the data (format) into excel then manipulate it with vba.
I want to learn vba so thats why I am attempting this - perhaps novice rather than newbie.
Thank you Rory

Ok! Rory. Thank you. I will play with these concepts to improve my understanding. I appreciate your time and effort.
I will get back to you with either more questions or my result.
+1