The antenna is best matched when its impedance is identical to the output
impedance of your amplifier (most 50 Ohm).
This matching can be done with series/parallel inductors and capacitors.
All you have to know is the impedance of your antenna at this frequency
(real and imaginary) and the output impedance of your amplifier.
The method described is to match a given antenna to the impedance of
your amplifier. This will give maximum power transmission and minimal
signal return (S11).
To match an antenna to a specified frequency you have to change the
dimension of your antenna. (How to make depends on the type of your
antenna). If the antenna is made shorter, the frequency will rise.
Depending on your operating frequency, I will suggest the use of the 1/4wave sleeve balun. The ARRL Radio amateur handbook is a good source to learn how to make it if you have access to the book.
I will be able to attach the diagram and procedure here on request if you need it desperately.