Multiply $ \color{blue}{2x} $ by $ \left( x^2-1\right) $ $$ \color{blue}{2x} \cdot \left( x^2-1\right) = 2x^3-2x $$

Multiply each term of $ \left( \color{blue}{2x^3-2x}\right) $ by each term in $ \left( 4x^2-2x-1\right) $.

$$ \left( \color{blue}{2x^3-2x}\right) \cdot \left( 4x^2-2x-1\right) = 8x^5-4x^4-2x^3-8x^3+4x^2+2x $$

Combine like terms:

$$ 8x^5-4x^4 \color{blue}{-2x^3} \color{blue}{-8x^3} +4x^2+2x = 8x^5-4x^4 \color{blue}{-10x^3} +4x^2+2x $$

Multiply each term of $ \left( \color{blue}{8x^5-4x^4-10x^3+4x^2+2x}\right) $ by each term in $ \left( 4x^2+2x-1\right) $.

$$ \left( \color{blue}{8x^5-4x^4-10x^3+4x^2+2x}\right) \cdot \left( 4x^2+2x-1\right) = \\ = 32x^7+ \cancel{16x^6}-8x^5 -\cancel{16x^6}-8x^5+4x^4-40x^5-20x^4+10x^3+16x^4+8x^3 -\cancel{4x^2}+8x^3+ \cancel{4x^2}-2x $$

Combine like terms:

$$ 32x^7+ \, \color{blue}{ \cancel{16x^6}} \, \color{green}{-8x^5} \, \color{blue}{ -\cancel{16x^6}} \, \color{orange}{-8x^5} + \color{blue}{4x^4} \color{orange}{-40x^5} \color{red}{-20x^4} + \color{green}{10x^3} + \color{red}{16x^4} + \color{orange}{8x^3} \, \color{blue}{ -\cancel{4x^2}} \,+ \color{orange}{8x^3} + \, \color{blue}{ \cancel{4x^2}} \,-2x = 32x^7 \color{orange}{-56x^5} + \color{orange}{26x^3} -2x $$