LED Driver IC Current Setting and Switching Frequency
You already have the datasheet.  Make use of it.
Here's the relevant section on the overvoltage protection feedback (OVFB) pin:


Pick your overvoltage level. (\$V_{OUT,OVP}\$)  This is a design choice made based on how much voltage would be too much.  Set it a bit higher than the worst case \$V_f\$ for your LED string.
Pick a value for one of \$R_{OVPH}\$ or \$R_{OVPL}\$ and solve the equation to get the other resistor value.  Keep in mind the 1 microampere pull up current.  You probably want to stay under 100k for each resistor.

For the current, you need to decide how (or if) you will do dimming.
The relevant sections:



If you dim by PWM or don't dim at all, then you set \$V_{ADIM}&gt;1.2V\$ and use \$I_{LED}= \frac{300mV}{R_{VFB}}\$
If you dim by analog input, then use the same equation (\$I_{LED}= \frac{300mV}{R_{VFB}}\$) to set the resistor for the current at maximum brightness.  The current through the LEDs is then given by  \$I_{LED}= \frac{0.3(V_{ADIM}-200mV}{R_{VFB}}\$.  You then vary \$V_{ADIM}\$ between 300mV and 1.2V to control the brightness (or 0 for off.)

You'll have to solve \$I_{LED}= \frac{300mV}{R_{VFB}}\$ to get the resistor value when given the current.
The switching frequency is your choice - the chip doesn't care.  It will influence your choice of the inductor and the FET, though.