as i can find the density by using the declared density chart in the CAO
however how would i use this data for TDR/LDR in the poh
Your POH probably requires pressure altitude (PALT) and temperature for entry into the performance charts.
So, take the density altitude (DALT) you derived from the CAO charts, and use the ISA model to convert it to a set of PALT and temperature numbers. Don't forget to add the elevation to the DALT value obtained from the chart.
A DALT of 2,000' for example, would be a PALT of 2,000' and temperature of 11 degrees C.