Despite the evidence for the effectiveness of neurofeedback (NFB) treatment, standardization is scarce, impairing comparability across studies and conditions. Therefore, the acceptance, satisfaction and feasibility of a standardized NFB manual with 14 sessions focused on sensory motor rhythm (SMR) reward and theta and high-beta reduction were evaluated. Methodology: This monocentric, prospective, interventional pilot study in an outpatient setting followed a mixed methods approach. Quantitative data were collected from patients through standardized questionnaires. Qualitative data were derived from interviews with NFB practitioners (NPs) and were analyzed using Mayring’s method of content analysis. Results: The analysis included 24 patients. The mean patient satisfaction (ZUF-8) was 20.81, reflecting moderate satisfaction. The average perceived system usability was 73.48, representing good acceptance. The majority (95.7%) of patients perceived the treatment to be feasible; 78.3% found it useful and would recommend it. Despite reoccurring technical difficulties, NPs perceived the manual to provide security and confidence during sessions. The clear instructions could partially compensate for the heterogeneity in expertise among NPs. Suggested improvements were intensified training on technical aspects and improved patient education. Conclusions: The developed NFB manual is a promising tool for delivering NFB in psychosomatic outpatient settings. It facilitates the establishment of standards, enhances quality assurance and ensures comparability across studies and treatments.