ADS1262 and 2.2 SPI TFT (Two SPI Slave) with Arduino
I would suggest that 

1) you debug individual code and to make sure that they work separately before integrating them.

2) you put those code pieces in logical blocks. for example, you are likely going to read something from the adc and displaying it on the lcd. so your code flow should be something like this:

  vol_adc = ad1262_read(ADC1_CH); //read analog from ADC1_CH
  vol_mv = adc2mv(vol_adc); //convert the adc results to mv
  lcd_display(vol_mv);  //display vol_mv on the lcd


this approach allows for much easier programming and debugging for you and your readers.