I got my first cat Noelle who is 1 year old now and decided I wanted another cat to keep her company. I got Marley who is ten years old today! They're both very sweet chill cats so I thought they'd get along. We first tried introducing them briefly by my mom holding Marley and Me holding Noelle. Noelle hissed at Marley so we stopped it their. Marley is now staying in the bathroom with all her things. Noelle will sit by the bathroom door watching her she hissed once. Then Noelle was swiping her paws under the bathroom door and Marley kind of went towards them and hissed. I've read a few posts on introducing cats but it seems like a lpt and I'm overwhelmed. Also i have no crate or gate for some of the steps. Marley is also getting restless being cooped up in the bathroom. Help??