Why you think you fail, because you get harmonics ? If so, why you think they invented filters. Every oscillator has harmonics. And 2 meters is not the most easy way to start.
Impedance in not that complex. They call it complex because in math it is a complex number, complex not as in difficult but complex like a block of houses together, i do not know the english word but something that looks like one part but is made from many parts. A skyscraper looks like one house but it are a whole bunch houses together. The skyscraper is Z it is one Real house and there are 1000 imaginairy houses inside it so in math a skyscraper is Z = ( 1 + j1000 )
This is mathamatical not correct but it should give the idea. Because you can write the absolute value of Z, noted as |Z| and that is the square root of ( R^2 + jX^2) and for a skyscraper that would give a funny number.
A capacitor and an inductor have a reactance, theire resistance for AC we call it X
The capacitor has a negative reactance, the inductor possitive.
Reactance is in math an imaginairy resistance and is written as jX ( in electronics, pure math uses iX but the letter i (from imaginair) is allready in use for current)
A resistor has real resistance, the kind you measure with an Ohm meter, we write it as R
If some component has real and imaginairy resistance we say it has a impedance ( and in fact, a component with only reactance is imaginairy

) we write that down as Z
Xc= 1/2pifC is the reactance of a capacitor
Xl = 2pifL is the reactance of an inductor
U=I X R and U = I x Z and because Z = R + jX you can wite U = I x ( R + jX)
For instance an inductor 100 uH on our LCR meter at 1 KHz
Measures R = 2 ohm at our ohm meter
So jX = 0.6283 Ohm
Z = 2 + j0.6283 , this is called a rectangulair notation because it are the lenght of two vectors.
The R in the Horizontal direction, so from left to right.
The jX in je vertical direction, up for positive anf down for negative.
We start with R at 0,0. in this case R goes 2 units to the right so that is R = (2,0) and from there X goes 0.6283 units up to (2,0.6283) if you draw to lines to the cordinates you have two vectors now draw a line from (2,0.6383) to (0,0) and we have a third vector. If we use phytagoras the lenght of that line is The squarroot ( x^2 + y^2) and that is the same formula you se for |Z|
and |Z| = 2.0964 so this the lenght of the vector and beause both units are in Ohm, |Z| is in Ohm too.
an other way to describe that vector as using rectangulir coordinates is to describe it in a polair notation. The length |Z| and the direction is in degrees. Arctan(X/R) = 17.4 degrees
The polar notation is now Z = 2.0964 and 17,44degrees
From there you know 90-17.4 = 72.56 degrees. This is loss angle, delta. And tan delta is 3.183 and called dissipation factor, called D or DF.
As you know Q is 1/DF so the Q of that coil at 1KHz is 1/3.183 =0.3141
Check : Q= X / Rs so 0.6283 / 2 = 0.3141 so the calculations are correct.
For a capacitor the same calculations ar true only this time the X vector goes down because it is negative.
You can draw the vectors on paper an just measure them.
If you have a series tank circuit you have two Impedances, ond from the C and onr from L. You can
Add them.Zl= (2+j0.6283)
and Zc we make (1-j2.5) at 1KHz
If you add those at 1KHz you get (3-j1.87)
I you calculate X for every frequency until Xl = Xc then the total Z = ( 3 + j0) so we only have the real part left. This state is called resonance. The lower R anfpd the higher jX and -jX are the higher the unloaded Q of the tank and that makes a stronger more stable oscillator.